Expanding on a suggestion from Sita, I've been toying around with concepts for the large C type revetments.
I still need to suck this model into 3ds-Max to remove some of the awkward surfacing, and to degrade some of the sharp edges. May also have to loose some of the barrel detail around the entrance but this gives you a general idea as to what I'm working towards.
Most pictures that I have found of WWII barrel lined revetments (fortifications) are dug into the terrain and the barrels act as shoring material to prevent the earth from collapsing back in, working with this concept I've placed a rammed earth berm feature around the structure.
